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Mach V Dan's mega suspension guide


Mach V Dan

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electrical issues? vw is known for all kinds of problems and that is one of the biggest complaints (http://www.usatoday.com/money/autos/2004-05-11-vw_x.htm) my friend had taken his car to the dealership 6 times in the past 5 months for all sorts of electrical problems.

 

I've driven VWs for decades. I've had my current '97 VW GTI-VR6 for ten years and I've never experienced any sort of electrical problems. But bashing/defending VWs is off topic for this thread. :offtopic:

 

The following is a taken from the Shine Racing Suspension site and is directed at primarily VW owners but seems to be relevant here since Subaru also uses MacPherson Struts.

 

Why Not Lower My Car?

 

VWs use a MacPherson Strut <http://en.wikipedia.org/wiki/MacPherson_strut> front suspension. The MacPherson design is extremely sensitive to ride height, and only really works at or about the factory ride height, when the control arms are level.

 

There are two critical geometric points to consider when discussing suspension performance: the center of gravity, and the roll center. The distance between these two points (the roll moment arm) determines the tendency of the car to roll.

 

The center of gravity moves with the ride height of the car. Lowering the car one inch will drop the center of gravity approximately eight tenths of an inch (only the sprung portion of the weight moves downward). The location of the roll center is a function of the suspension geometry. Lowering the body one inch on a Mk4 VW lowers the roll center approximately one and a half inches.

 

As a result of lowering the car 1 inch, the roll moment arm has increased more than half an inch, making it much easier for the car to roll.

 

When a car is allowed to roll, the resulting weight transfer decreases the available grip and keeps the car from handling to its potential.

 

 

So my questions is how much if any can a Legacy GT wagon be lowered from stock ride height before the control arms are no longer level and the handling is adversely effected?

 

The aftermarket wants to sell product so they will gladly sell you lowering springs & struts even if it adversely effects handling. :mad:

They know that the majority of owners who spend all that money to make the change won't admit if the handling has changed for the worse. Too many car ethusiast would rather look good than feel good.:dm:

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But bashing/defending VWs is off topic for this thread. :offtopic:

 

Um...quoting someone's article regarding VW suspension on a Legacy suspension thread is off topic for this thread.

 

Have you even looked underneath a Legacy? Do you have any specific information about this specific suspension? Do you even know what angle the control arms start out at?

 

The small amount of lowering I'd recommend on a Legacy (an inch or so) would be no more than the car would go through while going around a mild corner. The car certainly doesn't go all out of control if the suspension compresses an inch during cornering. Plus, lowering springs are firmer than stock -- this reducing any increased roll tendency from the lowered roll center. And if you are really, really concerned about negative lowering effects, you can install roll center adjusters, which will space those control arms back up where you like them.

 

--Dan

Mach V

FastWRX.com

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Um...quoting someone's article regarding VW suspension on a Legacy suspension thread is off topic for this thread.

 

Have you even looked underneath a Legacy? Do you have any specific information about this specific suspension? Do you even know what angle the control arms start out at?

 

The small amount of lowering I'd recommend on a Legacy (an inch or so) would be no more than the car would go through while going around a mild corner. The car certainly doesn't go all out of control if the suspension compresses an inch during cornering. Plus, lowering springs are firmer than stock -- this reducing any increased roll tendency from the lowered roll center. And if you are really, really concerned about negative lowering effects, you can install roll center adjusters, which will space those control arms back up where you like them.

 

--Dan

Mach V

FastWRX.com

 

It was my understanding that this thread was a general discussion of the pros & cons of different suspension modifications. Since Subarus do have MacPherson strut front suspensions I felt the write-up about sensitivity to ride height was relevant even if the write-up was originally done regarding VWs.

 

I appreciate the visual appeal of lower a vehicle as much as the next person but there are trade offs. I must have missed where you previously discussed what is an acceptable amount to lower. So I specifically asked the question how much if any can a Legacy GT wagon be lowered from stock ride height before the control arms are no longer level and the handling is adversely effected? It seems like that might be a question with a simple numeric answer...0.5 inches, 0.9 inches, 1.3 inches, 1.5 inches, etc., I don't know the answer so I asked the question. Do you know the answer?

 

You say you are only recommending lowering the car the same amount the suspension might compress while cornering. But that means you would need to stiffen the suspension a considerable amount to avoid having undesireable suspension geometry while cornering. If the suspension is stiffen wouldn't that adversely effect its ability to deal with any bumps it encounters? May be you live in an area where that is not a major concern. But unfortunately here in the Northeast smooth roads are hard to find and the ability of a suspension to soak up bumps while cornering is very important for good handling.

 

So I ask the question again how much is too much to lower a Legacy GT wagon for driving on NE roads when handling is more important than looks to the driver? :confused:

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It was my understanding that this thread was a general discussion of the pros & cons of different suspension modifications. Since Subarus do have MacPherson strut front suspensions I felt the write-up about sensitivity to ride height was relevant even if the write-up was originally done regarding VWs.

 

I appreciate the visual appeal of lower a vehicle as much as the next person but there are trade offs. I must have missed where you previously discussed what is an acceptable amount to lower. So I specifically asked the question how much if any can a Legacy GT wagon be lowered from stock ride height before the control arms are no longer level and the handling is adversely effected?

Between 1.0 and 1.5" would be the maximum I would lower the car without making any other geometry modifications. I would also advise stiffer shocks, especially if the car is at the lower end of that range..

 

You say you are only recommending lowering the car the same amount the suspension might compress while cornering. But that means you would need to stiffen the suspension a considerable amount to avoid having undesireable suspension geometry while cornering.
True. As I mentioned, all lowering springs that I know of are stiffer than stock. And I'd advise a shock that has stiffer dampening to match.

 

If the suspension is stiffen wouldn't that adversely effect its ability to deal with any bumps it encounters?
Yep. There's no free lunch. Lower = shorter suspension travel = less compliance = less ride comfort.

 

So I ask the question again how much is too much to lower a Legacy GT wagon for driving on NE roads when handling is more important than looks to the driver? :confused:
The best solution if you want better really-bumpy-road handling would probably be to have stiffer springs and shocks at the stock ride height. But nobody makes anything like that. So I'd say a good set of shocks (the Spec B Bilsteins or the Tokico HTS) and a set of mild lowering springs (JDM STi pinks, Swifts, Eibach) would be ideal.

 

Additional frame stiffening, with strut braces and undercarriage braces, would also improve handling even with stock suspension.

 

--Dan

Mach V

FastWRX.com

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The best solution if you want better really-bumpy-road handling would probably be to have stiffer springs and shocks at the stock ride height. But nobody makes anything like that.

If you can find JDM Spec B springs matched with Bilsteins, you CAN get significantly more stiffness without losing ride height. However in my opinion, extra spring stiffness is NOT necessarily your friend if one is always driving on bumpy roads, you end up LOSING control. I think higher damping rates will help, but to a point.

Would be good to know what setup the rally guys like to use. I know some criticize the new Impreza because it is not like the previous long travel set-up, it is now pretty much like the LGT.

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Between 1.0 and 1.5" would be the maximum I would lower the car without making any other geometry modifications. I would also advise stiffer shocks, especially if the car is at the lower end of that range..

 

True. As I mentioned, all lowering springs that I know of are stiffer than stock. And I'd advise a shock that has stiffer dampening to match.

 

Yep. There's no free lunch. Lower = shorter suspension travel = less compliance = less ride comfort.

 

The best solution if you want better really-bumpy-road handling would probably be to have stiffer springs and shocks at the stock ride height. But nobody makes anything like that. So I'd say a good set of shocks (the Spec B Bilsteins or the Tokico HTS) and a set of mild lowering springs (JDM STi pinks, Swifts, Eibach) would be ideal.

 

Additional frame stiffening, with strut braces and undercarriage braces, would also improve handling even with stock suspension.

 

--Dan

Mach V

FastWRX.com

 

Thanks for a very informative answer to my question. I had read at another location that Tein Comfort Sport coilovers were a popular alternative but wasn't sure if they met my selection criteria.

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  • 9 months later...

Springs determine the car's ride height, so changing to different springs can give a lowered ride height. Reduced ride height lowers the car's center of gravity some, which can increase cornering grip. It also reduces suspension travel, though, so the car may be less able to handle large bumps without bottoming out the suspension. Of course, there are the everyday issues of ground clearance to consider; stock cars don't scrape their chins on those concrete stopers in parking lots.

 

Sorry kind of a n00b question, but does lowering the car affect the size of the wheel/combo.

 

The reason I ask is because I had rubbing issues in the rear of my 97 LGT. The rear tires would rub on the bottom of the spring/strut assembly. I should note that my stock tire size is 205/55/16 and the rubbing occured with a 205/50/17, but I now have 205/45/17 and they are running fine on stock suspension set up.

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Sorry kind of a n00b question, but does lowering the car affect the size of the wheel/combo.

No.

 

The reason I ask is because I had rubbing issues in the rear of my 97 LGT. The rear tires would rub on the bottom of the spring/strut assembly. I should note that my stock tire size is 205/55/16 and the rubbing occured with a 205/50/17, but I now have 205/45/17 and they are running fine on stock suspension set up.

 

Hmm. What wheels are you using? Sounds like the offset is not quite the same as your original wheel. The 205/50R17 is less than 1% larger in diameter than your stock tire, so it should not cause rubbing unless you're using a wheel that's got a different offset.

 

205/45R17 is 2.5% smaller than stock. As a rule of thumb, I suggest staying within 2% of your stock tire size so as not to change your gearing and your speedometer/tachometer readings too much.

 

--Dan

Mach V

FastWRX.com

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  • 1 month later...
If putting on the COBB Sport Springs which are suposed to lower 1.75" front and 1" rear. How necessary is it to also change the struts? I dont track my car or drive it too hard. Are the stock struts on a legacy wagon non GT good enough? Also are the cobb springs a good way to lower?
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If putting on the COBB Sport Springs which are suposed to lower 1.75" front and 1" rear. How necessary is it to also change the struts? I dont track my car or drive it too hard. Are the stock struts on a legacy wagon non GT good enough? Also are the cobb springs a good way to lower?

 

In my experience, the stock Legacy shocks are not nearly firm enough to control the higher spring rates of a lowering spring like that. I'd go with Spec B Bilsteins or Tokico HTS adjustables.

 

I can't comment directly on the Cobb springs -- I haven't used them. I had thought they were out of production?

 

--Dan

Mach V

FastWRX.com

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i have a bushing in my right front endlink that has gone bad. debating between just replacing just the bushing or the whole endlink itself. question is, which should i replace and do i need to replace both front and rear( bushings and/or endlinks) at the same time? if i go endlinks and plan to buy aftermarket sways in the future should i just do the bushings for the time being until i have the whole setup bought? thanks man
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I'm not aware that the OEM endlink bushings are available separately; I think you have to get the whole endlink. You certainly do not have to change out front and rear at the same time. For that matter, if you're just replacing it with an OEM part, you could just replace the broken one.

 

--Dan

Mach V

FastWRX.com

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hmm gotcha. if i do go aftermarket endlinks w stock sway, will i have to get new endlinks when i do get a bigger sway, or are they "universal" cause im not seeing diff sizes or anything like that for an upgraded sway. so i shouldnt have any diff handling characteristics by only changing out the front? once again, thanks
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Endlinks are universal, in terms of fitting any diameter sway bar. (They're specific to the application -- that is, front of a Legacy GT -- but it doesn't matter how fat the sway bar is, as long as the link is strong enough.) The endlink just transmits force from the suspension to the sway bar and vice versa. You should not notice any change in handling from changing them out, unless your current ones are bent or broken.

 

--Dan

Mach V

 

hmm gotcha. if i do go aftermarket endlinks w stock sway, will i have to get new endlinks when i do get a bigger sway, or are they "universal" cause im not seeing diff sizes or anything like that for an upgraded sway. so i shouldnt have any diff handling characteristics by only changing out the front? once again, thanks
Edited by Mach V Dan
Clarified.
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  • 1 year later...

Thank you Dan for putting all the time and effort into making this information readily available. Of course there will be questions, and as I have read this and other threads, I still have concerns.

Here's my concern. I'm mounting 18x9.5 et38 wheels with 245/35s and as a roll.pull will be made, I still havent been able to figure out whether I need better struts with my Cobb springs, or just go coilovers. I don't necessairly need the height adjustment all the time, but I need a better ride, and I occasionally pull a motorcycle/utility trailer with several bikes loaded and as of now with my stock struts and Cobb springs, the rear tires can't even be seen. The car pulls whatever with no problem, but my suspension is suffering and I'm not exactly sure if I spend $1k on coilovers if that will be the best option or not. Would I need lateral links, rear camber bolts, butt shims, etc. I am on a budget and can't throw money around with my lacking military check. I also DD this and travel with the family in it. I don't want them suffering from an uncomfortable ride either. Thank you in advance to anyone that takes the moment to help me out here, it is and will be very much appreciated.

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  • 2 months later...

I hope you can help. I have an 07 Legacy 2.5i with 85K. My struts are leaking. I'm looking for a stock feel for my DD

1. Where can I find a "how to" guide to replace front & rear struts?

2. Who makes struts with a lifetime warranty? (a local shop is offering a NAPA strut supposedly with a lifetime warranty)

3. My rear end seems to sag a bit. How can I raise it maybe an inch or so? (I tow a small ATV trailer)...Maybe get some used Outback springs for the rear (on a tight budget) or do I need Outback springs in front too to raise the car in a level way?

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I realize it's been about 4 years since the last post here but I'm sure this thread as been read by many owners during that period. I'm one of them. I just wanted to go on record and thank you and the other contributors. I'm a brand new owner of a 2008 30.R Limited with 97,000 miles on her. At speed (No offense Ladies. I refer to my vehicles as females. Anything I love as much as my car or motorcycle has to be feminine.) she bottoms out easily over dips in the road that other cars barely notice, and the less said about potholes the better. Her body rolls more in the curves than I like, and she pushes in the tight ones.

 

My previous car, a 2001 Cadillac Catera Sport, had its ACDelco struts and shocks replaced with Yellow Koni Sports front and rear, along with 2006 Pontiac GTO springs which were stiffer and shorter by an inch. The front and rear ends also got polyurethane bushings where available. She had 90,000 miles at the time and was a little tired, understeering in turns, and shaking violently under braking. After the upgrades she felt reborn, a true German sport sedan, since underneath her Cadillac badging she was actually an Opel Omega MV6.

 

So far I've decided to replace the front & rear struts on my Legacy with fresh Bilstein B6s, along with thicker anti-swaybars F&R, fresh end links and tie-rod ends, Tein H-Tech lowering springs springs (.9 inch), and poly bushings all around. Naturally, I have a few questions.

  1. Whiteline has adjustable anti-swaybar endlinks, but I'm not sure what they accomplish by being adjustable.
  2. Whiteline also makes a Front Offset Top Mounts for lowered cars that alter the camber and caster settings. Would you recommend them?
  3. Whiteline has a Roll Center Kit that supposedly improves the handling to lowered cars. Worth it?
  4. I'm going with the Tribeca front anti-swaybar. What diameter rear bar would result in a slight bias towards oversteer? I prefer that to understeer.
  5. I've seen references to poly Steering Rack Bushings. What problem do they fix?

I'm still at the research stage so nothing is carved in stone (except for the front Lower Control Arm poly bushings I've already purchased). Answers to these questions will steer me to my car's eventual upgrades. I appreciate any and all advice. Thank you!

Edited by elvin315
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Keith Tanner at Flyin' Miata stated in one of his books that adjustable sway bar end links let you install the sway bar with no preload. You actually only need one adjustable end link to accomplish this.

 

john

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